Piston engines



T. HAHN v PISTON ENGINES `fune 26, 1962 5 Sheets-Sheet 1 Filed June l5,1959 /IVVE/VTOR {Luan- HJM.

`lune 26, 1962 T. HAHN 3,040,716

' PIsToN ENGINES Filed June l5, 1959 3 Sheets-Shoe?l 2 MS. 9cm@ June 26,1962 T. HAHN 3,040,716

PISTON ENGINES Filed June l5. 1959 Y 5 Sheets-Sheet 3 /NVENroR UniteStates Patent O 3,049,716 PISTON ENGINES Theodor Hahn, 97 Hauptstrasse,Sprockhovel, Westphalia, Germany Filed June 15, 1959, Ser. No. 820,164Claims priority, application Germany .inne 28, 1958 22 Claims. (Cl.121-59) This invention relates to a piston engine, which is particularlysuitable for use 'as a hydraulic motor 'and which has a plurality ofpiston-cylinder arrangements, which are constructed as telescopicallyextensible hollow bodies and which each independently bear by a pressureshoe against a crank with the interposition of a force and are yat theother end supported so as to be capable of swinging.

In 4a prior construction of piston engine of the above kind intended forthe idirect hydraulic ydrive of for example a tractor running wheel,cylinders are mounted in the wheel body radially so as to be swingableyabout axes parallel with the wheel axis, Aand in these cylinders aredisposed hydraulically operable pistons which bear by pressure shoesagainst partial regions of the surface of a supporting member disposedeccentrically in relation to the wheel, a sleeve mounted on rollersbeing inserted between the pressure surfaces of the pressure shoes andthe supporting member. The working chambers of the piston-cylinderarrangements are supplied with the working medium through pasagesprovided on the one hand in the supporting member and on the other handon the piston-cylinder arrangements. In this construction thepiston-cylinder arrangements are mounted positively on pins extending inparallel relationship to the axis of rotation of the `arrangement and inaddition to la complicated assembly this means that the arrangementrequires a great deal of space and permits only low power output. Inaddition, the operational dependability leaves much to be desired, sincethe supply system for the working medium provided in these circumstancescauses diiculty `and also results in a poor eiciency.

It has also been proposed to mount a star-shaped cylinder block on acrank positively so as to be rotatable, the bores which carry thepistons in the said cylinder block extending continuously to the crank.At the outer end, the pistons are supported on -a housing through themedium of piston rods. It has not been possible for such arrangements togain anyv practical importance, since the sealing of the workingchambers on the crank side is n'ot satisfactory and does not'last asufliciently long time. In addition, Yassembly is also diilicult withsuch arrangements. Moreover, very unfavourable stresses, which restrictthe power output, occur at the joints connecting the pistons to thepiston rods.

The object of the invention is to provide a piston engine of theabove-described kind which, while having a simple and compactconstruction, has a long life `and can be subjected to heavy loads, and,While requiring little space, gives high power output and Kalso takesoverloads without subjecting the bearing surfaces to unfavourably highstresses. To this end, according to the invention, the piston-cylinderarrangements are loaded by a force acting in the direction of extending,and are held at both ends in supporting bearings with the interpositionof a force. tion of the arrangement with only a few simple parts. Thepiston-cylinder arrangements associated with the engine form independentstructural `groups which can be installed and removed independently ofone another without further lassembly work. The operative position ofthe piston-cylinder arrangements is maintained by the force acting onthem in the extending direction. This force can be produced in variousways. It is, for ex- This gives a very simple and compact construcorrapid wear.

"lee

ample, possible to keep the working medium of the machine always under.a `certain positive pressure which produces the force acting in theextending direction which is necessary for the securing of thepiston-cylinder arrangements with the interposition of a force. As -arule, however, it is simpler to provide between the piston and thecylinder of the piston-cylinder arrangement a spring arrangement actingin the extending direction. A helical compression spring could, forexample, be used for this purpose. Instead of this, however, otherelastic members or arrangements couid also be provided.

The accommodation with the interposition of a force of the ends of thepiston-cylinder arrangements remote from the crank can `also be eifectedin various Ways. For example, the ends of the pistonecylinderarrangements remote from the crank can be mounted in knife-edgebeari-ngs or the like. It has proved particularly advantageous, however,to allow each of the piston-cylinder arrangements to rest by their endfaces remote from'the `crank on 'a supporting surface permitting atipping move- The force-effected supporting of the end of the pistoncylinder arrangement remote from the crank as proposed according to theinvention also oiers the advantageous possibility of considerablyreducing the bearing pressure in this region, the said bearing pressuregoverning the life and capacity of the arrangement to take load. Forthis purpose. it is advisable to provide the end face of thepiston-cylinder arrangement remote from the crank and forming a bearingsurface, with an aperture communicating with the working chamber andleading to adirect support of the working medium at the supportingsurface and enclosed by the bearing surface. In the region of thisaperture the working medium then presses directly on the supportingsurface, that is to say no mechanical lfriction occurs which might leadto wear and tear. The aperture is bounded by the bearing surface, sothat sealing satisfying `all requirements is automatically obtained. Infurther development of this principle, the end of the piston-cylinderarrangement remote from the crank and the associated supporting surfacemay have recesses which jointly form a part of a passage carrying theworking medium. This enables the working medium to be `fed to thepiston-cylinder larrangement in a very simple and economical manner,while the supporting pressure is utilised directly 'for the purpose ofysealing 0E the movable connection.

Moreover, the pressure shoe of the piston-cylinder arrangement mayequivalently have an aperture communicating with the working chamber andleadingto a direct support of the working medium on the crank andenclosed by the bearing surface of the pressure shoe. In this way, adirect supporting of the working medium on the crank or a sleeve mountedrotatably on the latter in manner known per se is also obtained at thisend of the piston-cylinder arrangement andreduces the mechanical surfacepressure and hence the wear occurring during operation. This isparticularly important in the region of the supporting of thepiston-cylinder arrangement on the crank side, since in this regionconsiderable speeds occur during the operation of the arrangement and inthe comparable previously known piston engines result either inunfavourable limitation of the working pressure These diiculties arefundamentally obviated by the direct supporting of the working mediumaccording to the invention. With such arrangements 1t may, of course, beadvisable to provide a cross-sectional constriction between the workingchamber of the pistoncylinder arrangement and the aperture provided inthe bearing surface of the pressure shoe. The effect thereby achieved isthat in the event of any unintentional lifting of the pressure shoe fromthe crank, for example as the result of faulty operation of thearrangement or through a fault in the supply of the working medium, thepositive pressure present in the working chamber and acting on thepiston-cylinder arrangement in the stretching direction cannotcompletely collapse. The operational dependability is thus maintainedeven in unfavourable circumstances. Y

The size of the apertures in the bearing surfaces of the piston-cylinderarrangement respectively facing and remote from the crank can be adaptedto the size of the appertaining axial projection surface of the Workingchamber so as to produce a surface pressure suicient for sealingpurposes and originating primarily from the pressure of the workingmedium. This enables the mechanical pressure always to be limitedindependently of the working pressure of the arrangement in such mannerthat while adequate sealing occurs the mechanical friction neverthelessremains below the permissible limits. The specific loadingcan be madeparticularly low when the end face bearing surfaces also have elasticpackings inserted. Very low pressures are then suliicient for dependablesealing. In addition to or instead of this the sealing can also beimproved by contriving grooves enclosingy the apertures in the end facebearing surfaces of the piston-cylinder arrangements. The groove spacesare advantageously connected tothe pressure-free space by conduits. Inthis way cushions of pressure oil or the like, which might impair thesealing, are prevented from forming at the slide surfaces. Such'constructions are advantageous especially for the running surface ofthe pressure shoe.

The inventioncan successfully be embodied in piston engines of varioustypesV of construction. According to one preferred embodiment it isproposed to allow at least two piston-cylinder arrangements supportedwith the interposition of a force at the outer end in a fixed housingand lying in a common radial plane Vto co-operate jointly with a crankof the shaft. When in such arrangements at least three piston-cylinderarrangements are provided for a crank, a machine is obtained having aVery uniform reception for the working'rnedium and capable of startingautomatically from .any position. It is, however, also possible todispose one behind the other a plurality of groups of piston-cylinderarrangements. In this way, while-the complete arrangement requireslittle space, high torques can be produced when the machine isconstructed as a motor and high deliveries when constructed as a pump.

Piston engines of the kind according to the invention which have atleast three piston-cylinder arrangements lying jointly in a radialplane, are advantageously constructed with a housing in the form of abody of rotation. It is possible, however, to allow the piston-cylinderarrangements to co-operate in each case by pairs with one crank, theirends remote from the crank being situated diametrically opposite to oneanother with respect to the shaft. It is then more favourableto make thehousing flat, this giving extremely small overall dimensions. In sucharrangements, a plurality of pairs of piston-cylinder arrangements areadvantageously disposed with the same basicV longitudinal direction oneafter the other which co-operate with cranks offset in relation to oneanother in the direction of rotation.- A preferred embodiment of such amachine provides three cranks, which are each offset by 120 Yin relationto one another and are each subject to the action of two piston-cylinderarrangements which are directed in opposition, and the supports ofwhich, remote from the cranks, all lie in an axial plane in relation tothe shaft. This gives the decisive advantage that the stresses on thebearings of the machine shaft remain extremely low.

The piston machines according to the invention may also be constructeddiiferently inasmuch as it is possible either to drive in relation to astationary housing a shaft carrying the crank or cranks or else to allowthe facing ends of the piston-cylinder arrangements to rest on astationary bearing member and to ,guide the supporting body enclosingthe piston-cylinder arrangements and securing their outer ends so as tobe rotatable eccentrically in relation to the axis of the bearingmember. This latter construction is advantageous in so far as thesupporting body constructed as a body of rotation can directly form apart of an energ -transmitting structural part, such as a rope drum orthe like. Clutches and the like may thus be dispensed with so that thecomplete arrangement, while giving high performance, remains light andcompact and has a good efficiency.

It has already been stated that it is advantageous in the arrangementaccording to the invention to supply the working medium to thepiston-cylinder arrangement a-t the outer end which is supported soas tobe capable of swinging. The control may be eifected by a rotary valverigidly coupled directly .to the rotating part of the machine. Insteadof this, however, it is also possible to use a separate valvearrangement rotating synchronously with the machine. A rotary :valvearrangement coupled directly to the rotating part of the machine ispreferable as a rule, since it enables the arrangement to be madeparticularly compact. To this end, the rotary valve arrangement and thehousing supporting the piston-cylinder arrangement at the outer end mayhave passages therein for the working medium, the inlets of whichpassages, lying in side faces, coincide with one another after thecoupling of the housing parts. In this Way, exposed pipelines or thelike can las a rule be completely dispensed with, so that the machinehas an untrammelled appearance and damage rarely occurs even withunusual stresses.

In order that the invention may clearly be understood and carried intoeect the same will now be described by aid of the accompanying drawingsin which:

FIGURE l is a side elevation, in partial section, of a piston enginewhich can be used particularly as a hydraulic motor.

FIGURE 2 shows in longitudinal section, a rope winch with directlyconnected hydraulic motor,

FIGURE 3 is sectional View of a piston engine according to a furtherembodiment,

FIGURE 4 is a diagrammatic View of the control of the piston engineshown in FIGURE 3.

The piston engine shown in FIGURE l has a shaft 12 which is mountedrotatably in side walls 10 of a substantially annular housing orabutment means 11 and which carries a crank 13 constructed as aneccentric. The casing of the housing 11 has on the inside threedome-shaped depressions 14, which are arranged uniformly around theperiphery and in each of which is located a cylinder 15 by itsspherically shaped outer end 16. Each cylinder end 16 is boredlongitudinally to form ahollow body and carries an elastic packing 17which surrounds the bore and which bears against the dome 14 so as toseal. The housing 11 contains for each pistoncylinder arrangement aworking medium supply passage i8 which is formed by bores and whichleads into the dome 14. -In the cylinder 15 a piston in the form of ahollow body 19 is guided to be longitudinally slidable and its free endis supported by a pressure shoe 20 against a bush 21 rotatable on theeccentric 13` preferably with the interposition of anti-friction Ibodiessuch as needle bearings. The bearing face of the pressure shoe 20surrounds in the form of a ring a central aperture 22 which communicateswith the working chamber of the pistoncylinder arrangement through arelatively narrow passage 23. Moreover, annular grooves 24, 25 areprovided in the slide face of the pressure shoe and communicate with theinteriorof the housing through passages 26. Between an end 27 of thepiston 19- containing the passage 23 and an annular disc 28 inserted inthe cylinder is interposed a compression coil spring 29 which isprestressed in the direction of extending of the pistoncylinderarrangement and maintains the operative position of the piston-cylinderarrangement which is supported at both ends solely with theinterposition of a force, the said position being maintained even whenthe working chamber of said arrangement is pressureless. A spring ofthis kind could be dispensed with if the arrangement can always be keptunder a positive pressure. The ratio of the size of the bearing `facesto the apertures or recesses giving a direct support of the workingmedium is selected, taking into account the size of the piston surfacesexposed to the pressure of the working medium on the one hand, and ofthe cylinder on the other hand in such manner that mechanical `frictionis kept below the permissible limit but dependable sealing is stillobtained. The sealing pressure in these circumstances rises with theworking pressure so that a dependable sealing is obtained under 'alloperating conditions. The crosssectional constriction 23 providedbetween the working chamber of the piston-cylinder arrangement and therecess 22. is intended to prevent collapse of the working pressure in`the cylinder-piston arrangement in the event of any lifting of thepressure shoe 20 away from the bush 21 in consequence of faultyoperation or damage, the ow of working medium through the passage 23being limited.

By means of a rotary valve (not shown in detail in the drawing), whichmay be coupled to the shaft 12, the piston-cylinder arrangements aresuccessively connected alternately to the supply of pressure uid and thedischarge line, so that the shaft 12 is driven continually. For thismode of operation it is not absolutely necessary for the end face of thecylinder to have a bore which renders possible direct support of theworking medium in the dome 14. Nor is it necessary to provide anaperture 22 in the pressure shoe Ztl. These constructions afordconsiderable advantages, however, inasmuch as they enable very highpressures of the working medium to be used, that is to say high powersto be obtained with small dimensions for the arrangement. Moreover,packings 17 or grooves 24, 25 may be dispensed with.

In the arrangement of FIGURE 2 which shows a combined unit consisting ofa winch and hydraulic motor a shaft 3S is held in la bearing bracket 36so as to be rigid in respect of rotation. Bushes 39 are mountedrotatably on an eccentric 37 of the shaft 3S through the medium ofneedle rollers 3S and co-operate in each case with three piston-cylinderarrangements 450 of the type already described in connection with FIGUREl, -the said pistoncylinder arrangements lying in the form of stars intwo parallel radial planes. The free end of the shaft is constructed asa spigot 41 which represents a bearing member for a housing or abutmentmeans 42 which is constructed substantially as a body of rotation andwhich is mounted on the other hand on the part of the shaft 35 facingthe bearing bracket 36. In this housing the outer ends of thepiston-cylinder arrangements 4t) are accommodated with the interpositionof a force so as to be capable of swinging in the manner alreadydescribed in connection with FIGURE 1. Rigidly connected to the sidewall 43 of the housing 42 centrally in relation to the axis of thespigot 41 is a drum 44 which is provided with a side disc 45 at its freeend and is mounted rotatably on a stub shaft 46 carried by a bearingbracket 47. The stationary shaft 35 carries a directly attached member4S, which in co-opera-tion withan appropriate construction of the sidewall 49 of the housing forms a rotary valve controlling the distributionof the working medium. To this end, two grooves 5G extending in a commonradial plane in the peripheral direction are provided in the member 48of the shaft 35. Said grooves are each connected by means oflongitudinal bores passing lthrough the shaft end, to a conduit 51supplying the working medium. In the region of the grooves radiallyextending bores 52 are provided in the housing wall 49 and in dependencyon the rotary position supply and discharge the working medium for theindividual pistoncylinder arrangements through further bores 53.Associated with the grooves 50 are relief grooves 54 which are connectedto the passages carrying the working medium in such manner that thepressure difference of the said working medium between the supply anddischarge sides cannot produce any unilateral bearing pressures.

The hydraulic motor forming the basis of FIGURES 3 and 4 of the drawinghas a at box-shaped housing or abutment means 60, which has preferablydetachable side walls 61. Formed in the latter, lying in a row in eachcase, are dome-shaped depressions 62, each of which accommodates theouter end of a piston-cylinder arrangement 63 of the type alreadydescribed, with the interposition of a force. In the housing side walls64 and 65 a shaft 66 is mounted rotatably which carries eccentrics 67,68 and 69 which form cranks and which are v oifset in relation to oneanother by 120 in each case in the peripheral direction. Against theseeccentrics bear the pressure shoes of the cylinder-piston :arrangements63 which each co-operate by pairs with an eccentric and the outer endsof which are situated diametrically opposite one another with respect tothe axis of the shaft 66, while -in addition all the dome-shapeddepressions 62. of the housing are `disposed in a common plane passing-through the axis of the shaft 66. This gives a very compactconstruction, since the housing 60 requiresV only a small height.Rigidly coupled to the shaft 66 by a coupling projection .70 is a rotaryvalve 71 rotatable'in a bush 72 mounted rigidly in a housing 73.Connected to the housing 73 in unions 74 and 75 are the conduitscarrying the working medium. The latter flows through bores 76 and 77respectively passing through `the bush 72 into annular passages 7? and79 respectively of the rotary valve, which are connected, bylongitudinal bores, not shown, to approximately semi-circular grooves 80and 81 and relief grooves of the type already described associated withthese. In the common plane of rotation of the grooves 80 land S1 boresS2 are provided in the bush 7?., being distributed over the periphery,and are connected to the inlet apertures of the cylinder-pistonarrangements through further passages $3, 84, 85. The passage 835-85 areso disposed that they directly complement one another when the housingpart 73 is connected to the housing 61. The control of the arrangementis shown in FIGURE 4 in particular. On the rotation of the rotary valve7l in the bush 72 the individual piston-cylinder arrangements `aresuccessively connected alternately to the pressure iiuid line and thedischarge line. The overlaps of the conduits, which will be seen inFIGURE 4 and which could be directly contrived in the housing parts onlywith diiculty, are according to FIGURE 3 avoided by groovesappropriately disposed on the outer surface of the bush 72 and extendingbetween the bores 82 and the corresponding housing bores, so that theprovision of the passages Within the housing parts affords nodifficulty.

As already stated, the constructions illustrated are only particularembodiments of the invention. The latter is not restricted thereto. Onthe contrary, many other constructions and applications are possible.The invention can be equivalently embodied for pumps serving forhydraulic purposes especially, although the application to hydraulicmotors offers special advantages. Modiiications are possible, forexample by supporting the cylinders of the piston-cylinder arrangementon the crank pin or the supporting member associated with the facingends ofthe piston-cylinder arrangements, while the pistons are directedtowards the outsides. The crosssectionai constrictions or passages 23,which are variable if required, of the kind shown in FIGURE 1, could bedispensed with, that is to say it would `be possible to allow theworking chambers of the piston-cylinder arrangements to extendunthrottled as far as the bush 21 or the crank pin 13. On the otherhand, the pistons could also be closed in the region of their pressureshoes 2%. 'In equivalent manner, the cross-section of the bores passingthrough the cylinder ends could be limited in such manner that only aregular supply and discharge of the pressure medium takes place. inarrangements according to FIGURES 1 and 2, it would be possible for agreater or lesser number of piston-cylinder arrangements than threelying in a radial plane to co-operate with the shaft or Vthe supportingmember. Moreover, it is possible to connect successively in each case asmany groups of piston-cylinder arrangements as required to achieve thedesired power. The piston-cylinder arrangements may in thesecircumstances co-operate with one or more crank pins.V The devicescontrolling the distribution of the working medium may be modified inmany ways and, if required,V be accommodated outside the actual engine.

What I claim is:

1. A piston engine comprising, in combination, shaft means includingeccentric crank means; a plurality of iioating piston-cylinderarrangements each comprising a pair of telescopically extensible hollowbodies and each having a first and a second end; a pressure shoeprovided at the rst end of each piston-cylinder arrangement; abutmeutmeans adjacent the second ends of said arrangements; and means forbiasing the bodies of said arrangements in a direction away from eachother to thereby respectively press said shoes against said crank meansand the second ends of said arrangements against said abutment means,said arrangements retained between said crank means and .said abutmentmeans solely by the action of said biasing means.

2. A piston engine comprising, in combination, shaft means includingeccentric crank means; a plurality of floating piston-cylinderarrangements each comprising a hollow cylinder and ahollow pistontelescopicallyV received in said cylinder, each piston-cylinderarrangement having a first and a second end; -a pressure shoe providedat the iirst end of each piston-cylinder arrangement; abutment meansadjacent the second ends of said piston-cylinder arrangements; andspring means inserted between the cylinder and piston of eacharrangement for respectively biasing said pressure shoes against saidcrank means and thesecond ends of said arrangements against saidabutment means, said arrangements retained between said crank lmeans andsaid abutment means solely by the action of said springs.

3. A piston engine comprising, in combination, shaft means includingeccentric crank means; a plurality of iioating piston-cylinderarrangements each comprising a pair of telescopically extensible hollowbodies and eachV having a rst and a second end; a pressure shoe providedat the rst end of each piston-cylinder arrangement; abutment meansadjacent the second-ends of said arrangements; and means for biasing`the bodies of said arrangements in a direction away from each other tothereby respectively press said shoes against said crank means and thesecond ends of said arrangements against said abutmeans, said'abutmentmeans formed with supporting surface means permitting tipping movementsof said arrangements with vrespect thereto, said arrangements retainedbetween said crank means and said abutment means solely by the action ofsaid biasing means.

4. A piston engine comprising in combination, shaft means includingeccentric crank means; a plurality of ioating piston-cylinderarrangements each comprising a pair of telescopically extensible hollowbodies and each having a first end and a curved second end; a pressureshoe provided at the iirst end of each piston-cylinder arrangement;abutment means adjacent the second ends of said arrangements; and meansfor biasing the bodies of said arrangements in a direction away fromeach other to thereby respectively press said shoes against said crankmeansrand the second ends of said arrangements against said abutmentmeans, said abutment means formed with curved supporting surface meansengaging with the curved ends of said arrangements, said arangementsretained between said crank means and said abutment means solely by theaction of said biasing means.

5. The piston engine as set forth in claim 4, wherein the second ends ofsaid arrangements and said supporting. surfaces are spherical.

6. A piston engine comprising, in combination, shaft means includingeccentric crank means; a plurality of floating piston-cylinderarrangements each comprising a pair of telescopically extensible hollowbodies deining a working chamber and each arrangement having a first anda second end, each said second end formed with aperture meanscommunicating with the respective chamber; a pressure shoe provided atthe rst end of each pistoncylinder arrangement; abutment means adjacentthe second ends of said arrangements and formed with passages for aworking medium in communication with the lrespective aperture; and meansfor biasing the bodies of said arrangements in a direction away fromeach other to thereby respectively press said shoes against said crankmeans and Ito sealingly press the second ends of said arrangementsagainst said abutment means, said arrangements retained between saidcrank means and said abutment means solely by the action of said biasingmeans.

7. A piston engine comprising, in combination, shaft means includingeccentric crank means; a plurality of floating piston-cylinderarrangements each comprising a pair of telescopically extensible hollowbodies defining a working chamber and each piston-cylinder arrangementhaving a first and a second end; a pressure shoe provided at the firstend of each piston-cylinder arrangement; abutment means adjacent thesecond ends of said arrangements, said abutment means and said secondends formed with recesses constituting passages for a working medium tosaid working chambers; and means for biasing the bodies ofV saidarrangements in a direction away from each other to thereby respectivelypress said shoes against said crank means and to sealingly press thesecond ends of said arrangements against said abutment means, saidarrangements retained between said crank means and said abutment meanssolely by the action of said biasing means.

8. A piston engine comprising, in combination, shaft means includingeccentric crank means; a plurality of iioating piston-cylinderarrangements each comprising a pair of telescopically extensible hollowbodies defining a working chamber and each pistomcylinder arrangementhaving a first and a second end; a pressure shoe provided at the firstend of each piston-cylinder arrangement, each pressure shoe formed withaperture means communicating with the respective working chamber andeach pressure shoe also having a bearing surface surrounding therespective aperture means; abutment means adjacent the second ends ofsaid arrangements, said abutment means and said second ends formed withrecesses constituting passages for a working medium to said workingchambers; and means for biasing the bodies of said arrangements in adirection away from each other to thereby respectively press the bearingsurfaces of said shoes into sealing engagement withV said crank means toprevent discharge of working medium between the pressure shoes and thecrank means and to sealingly press the second ends of said arrangementsagainst said abutment means, said `aperture -means permitting directcontact of the working medium with said crank means and the ratiobetween the cross-sectional areas of the aperture means and of therespective working chambers being such that a surface pressure suticientfor sealing purposes is produced between said shoes and said crankmeans, said `surface pressure originating primarily trfom the pressureof the working medium.

9. A piston engine comprising, in combination, shaft means includingeccentric crank means; a plurality of piston-cylinder arrangements eachcomprising a pair of telescopically extensible hollow bodies defining aworking chamber .and each piston-cylinder arrangement having afrrst anda second end; a pressure shoe provided at the first end of eachpiston-cylinder arrangement; abutment means adjacent the second ends ofsaid arrangements, said abutment means and said second ends formed withrecesses constituting passages for a working medium to said workingchambers; elastic packing means mounted in and surrounding the recessesof the second ends of said piston-cylinder arrangements; and means forbiasing the bodies of said arrangements in a direction away from eachother to thereby respectively press said shoes against said crank meansland to sealingly press said packing means against said abutment means.

10. The piston engine as set forth in claim 7, wherein said pressureshoes are formed with apertures communieating with the respectiveworking chambers and with bearing surfaces surrounding said aperturesand sealingly engaging with said crank means to prevent discharge ofworking medium between the pressure shoes and the crank means, saidapertures permitting direct contact of the working medium with saidcrank means.

r11. A piston engine comprising, in combination, shaft means includingeccentric crank means; a plurality of piston-cylinder arrangements eachcomprising a pair of telescopically extensible hollow bodies defining aworking chamber and each pistoncyinder arrangement having a first and asecond end; a pressure shoe provided at the first end of eachpiston-cylinder arrangement, each pressure shoe formed with `aperturevmeans communicating with the respective working chamber and eachpressure shoe having a bearing surface surrounding the respectiveaperture means; means defining a cross-sectional constriction for theworking medium between the aperture means of each pressure shoe and therespective working chamber; abutment means adjacent the second ends ofsaid arrangements, said abutment means and said second ends formed withrecesses constituting passages for a working medium to said workingchambers; and means for biasing the bodies of said arrangements in adirection away from each other to thereby respectively press the bearingsurfaces of said shoes into sealing engagement with said crank means toprevent discharge of working medium between the pressure shoes and thecrank means and to sealingly press the second ends of said arrangementsagainst said abutment means, said aperture means permitting directcontact of the working medium with said crank means.

12. A piston engine comprising, in combination, shaft means includingeccentric crank means; a plurality of piston-cylinder arrangements eachcomprising a pair of telescopically extensible hollow bodies defining aworking chamber and each piston-cylinder arrangement having a first endand a second end; a pressure shoe provided at the first end of eachpiston-cylinder arrangement, each pressure shoe formed with aperturemeans communicating with the respective working chamber and having abearing surface surrounding said aperture means, said bearing surfacesformed with grooves surrounding the respective aperture means; abutmentmeans adjacent the second ends of said arrangements, said abutment meansand said second ends formed with recesses constituting passages for aworking medium to said working chambers; and means for biasing thebodies of said arrangements in a direction away from each other tothereby respectively press the bearing surfaces of said shoes intosealing engagement with said crank means to prevent discharge of workingmedium between the pressure shoes and the crank means and to sealinglypress the second ends of said arrangements against said abutment means,said aperture means 10 permitting direct contact of the working mediumwith said crank means.

13. A piston engine as set forth in claim 12, wherein said shoes areformed with passages connecting said grooves with the atmosphere.

14. A piston engine comprising, in combination, a stationary housing;shaft means including eccentric crank means rotatably mounted in saidhousing; at least two floating piston-cylinder arrangements disposed ina common plane radial with respect to said shaft means, each arrangementcomprising a pair of telescopically extensible hollow bodies Yand eachhaving a rst and a second end; a pressure shoe provided at the first endof each pistoncylinder arrangement; and means for permanently biasingthe bodies of said pistoncylinder arrangements in a direction away fromeach other to thereby respectively press said shoes against said crankmeans and to press the second ends of said arrangements into abutmentwith said stationary housing, said arrangements retained between saidcrank means and said housing solely by the action of said biasing means.

15. A piston engine comprising, in combination, a stationary housing;shaft means including eccentric crank means rotatably mounted in saidhousing; at least two Y groups of iioating piston-cylinder arrangements,each group disposed in a common plane radial with respect to said shaftmeans, each arrangement comprising a pair of telescopically extensiblehollow bodies and each having a first and a second end; a pressure shoeprovided at the first end of each piston-cylinder arrangement; and meansfor permanently biasing the bodies of said piston-cylinder arrangementsin ya direction away from each other to -thereby respectively press saidshoes against said crank means and to press the second ends of saidarrangements into abutment with said stationary housing, saidarr-angements retained between said crank means and said housing solelyby the action of said biasing means.

16. A piston engine comprising,v in combination, a stationary housing;shaft means including eccentric crank means and rotatably mounted insaid housing; at least one group of floating piston-cylinderarrangements, each said group comprising two -arrangements disposeddiametrically opposite with respect to said shaft means in a commonradial plane, each piston-cylinder arrangement cornprising a pair oftelescopically extensible hollow bodies and each arrangement having afirst and a second end; a pressure shoe provided at the first end ofeach piston-cylinder arrangement; and means for permanently biasing thelbodies of said piston-cylinder arrangements in a direction away fromeach other to thereby respectively press said shoes against said crankmeans and to press the second ends of said 4arrangements into abutmentwith said stationary housing, said arrangements retained between saidcrank means and said housing solely by the action of said biasing means.

17. A piston engine comprising, in combination, a stationary housing;shaft means including a plurality of eccentric cranks and rotatablymounted in said housing; a

plurality of groups of floating piston-cylinder arrangements, one foreach of said cranks, each said group comprising two arrangementsdisposed diametrically opposite with respect to said shaft means in acommon radial plane, each piston-cylinder arrangement comprising `a pairof telescopically extensible hollow bodies and each arrangement having afirst and a second end; a pressure shoe provided at the first end ofeach piston-cylinder arrangement; and means for permanently biasing thebodies of said piston-cylinder arrangements in a direction away fromeach other to thereby respectively press saidv shoes against `therespective cranks and to press the second ends of said arrangements intoabutment with said stationary housing, said arrangements retainedbetween said housing and the respective cranks solely by the action ofsaid biasing means.

18. A piston engine comprising, in combination, a stal. l tionaryhousing; shaft means including three cranks and rotatably mounted insaid housing, said cranks otset by 120 in relation to each other; threegroups of oating piston-cylinder airangementsfone foreach of saidcranks, each group comprising two oppositely directed pistoncylinderarrangements disposed diametrically opposite with respect to said shaftmeans in a common radial plane, each said arrangement comprising a pairof telescopically extensible hollow bodies and each arrangement having arst and a second end witlrsaid second ends located in a common axialplane in relation to said shaft means; a pressure shoe provided at therst end of each pistoncylinder arrangement; and means for permanentlybiasing the bodies of said piston-cylinder arrangements ina directionaway from each other to thereby respectively press said shoes againstthe respective cranks and to press the second ends of said arrangementsinto abutment with said stationary housing, said arrangements retainedbetween said housing and the respective cranks solely by the action ofsaid biasing means.

19. A piston engine comprising, in combination, stationary shaft meansincluding eccentric crank means; av

supporting body surrounding said crank means and rotat-V able coaxiallyabout said shaft means; a plurality of oating piston-cylinderarrangements each comprising a pair of telescopieally extensible hollowbodies and each having a iirst and a second end; appressure shoeprovided at the iirst end of each said ararngement; and means forbiasing the bodies of said arrangements in a direction away from eachother to thereby respectively press said shoes against said crank meansand to press the second ends of said arrangements into abutment withsaid supporting body, said arrangements retained between said supportingbody and said crank means solely by the action of said biasing means.

20. A piston engine comprising, in combination, stationary shaft meansincluding eccentric crank means; an energy transmitting member includinga supporting body of rotation, said body surrounding said crank meansand rotatable coaxially about said Vshaft means; a plurality of floatingpiston-cylinder arrangements each comprising a pair of telescopicallyextensible hollow bodies and each having a first and a second end; apressure shoe provided atthe first end of each said arrangement; andmeans for biasing the bodies of said arrangements in a direction `awayfrom each other to thereby respectively press said shoes against saidcrank means and to press the second ends of said arrangements intoabutment with said supporting body, said arrangements retained betweensaid supporting body and said crank means solely by the action of saidbiasing means. t

21. A piston engine comprising, in combination, shaft means including atleast one eccentric crank; a plurality of floating piston-cylinderanrangements each comprising a pair of telescopically extensible hollowbodies defining a working chamber therebetween, each said arrangementhaving a rst end and a second end; a pressure shoe provided at the iirstend of each said arrangement; abutment means adjacent the second ends of4said arrangements, one of said `means rotatable with respect to theother means; Valve means for controlling the supply and discharge of aworking medium to said chambers, said valve means coupled with saidrotatable means; and means for biasing the lbodies of said arrangementsin a direction away from each other to thereby respectively press saidshoes against said crank and to press the secc-nd ends of saidarrangements against said abutment means, said arrangements re# tainedbetween said crank and said abutment means solely by the action of saidbiasing means.

22. A piston engine comprising, in combination, shaft means including atleast one eccentric crank; a plurality of iioating piston-cylinderarrangements each comprising a pair of telescopically extensible hollowbodies defining a working chamber therebetween, each said arrangementhaving a irst end and a second end; a pressure shoe provided at the rstend of each said arrangement; multi-section housing means adjacent thesecond ends of said arrangements, one of said means rotatable withrespect to the other means and said housing means formed with passagesfor conveying a working medium to and from said working chambers, saidpassages formed between the sections of said housing means; valve meansfor controlling the supply md discharge of a working medium to saidchambers, said valve means coupled with said rotatable means; and meansfor biasing the ybodies of said arrangements in a direction away fromeach other to thereby respectively press said shoes against said crankand to press the second ends of said arrangements into abutment withsaid housing means, `said arrangements retained between said housingmeans and said crank solely by the action of said biasing means.

References Cited in the le of this patent UNITED STATES PATENTS 386,548Mather July 24, 1888 649,301 Hardie et al May 8, 1900 702,601- SmithJune 17, 1902 1,562,769 Hubbard Nov. 24, 1925 2,347,663 Carnahan May 2,1944 2,662,374 Woydt Dec. l5, 1953 FOREIGN PATENTS 820,430 Germany Nov.12, 1951

